The present invention relates to a fluid dispenser device serving to be mounted on a receptacle containing the fluid to be dispensed. The invention relates more particularly to a dispenser comprising a fluid pump defining a pump chamber of variable volume, an inlet valve making it possible for the fluid to enter into the pump chamber, an outlet valve making it possible for the fluid under pressure to exit from the chamber, and a dispensing orifice downstream from the outlet valve. This is an entirely conventional design for a dispenser that can, for example, be used in the fields of perfumes, of cosmetics, or of pharmaceuticals.
The present invention relates more specially to the outlet valve of the dispenser. Such an outlet valve conventionally comprises a valve seat and a moving valve member serving to come into leaktight abutment against the valve seat. The moving valve member lifts off its seat when the pressure inside the chamber exceeds a certain threshold. The fluid under pressure inside the chamber can then be delivered through the valve to the dispensing orifice. The pressure threshold for opening the outlet valve is in general determined by thrust means that press the moving valve member against its seat. The thrust means can, for example, be in the form of a spring, which can be a cylindrical or spiral metal spring, or else a plastics spring in any shape whatsoever.
The moving valve member is, in general, a passive member in that it does not participate directly in delivering the fluid to the dispensing orifice. On the contrary, the moving valve member serves merely as a stopper to close off the pump chamber when the pressure inside the chamber is lower than the predetermined pressure threshold. As soon as the pressure exceeds said threshold, the moving valve member moves off its seat and the fluid can flow between the seat and the moving valve member to the dispensing orifice. The delivered fluid thus flows on either side of or all around the moving valve member. It can thus be said that the moving valve member is totally passive during dispensing of the fluid. And, as soon as dispensing is finished, the moving valve member returns to its leaktight position on its seat.
An object of the present invention is to define a dispenser whose outlet valve has a moving valve member that participates actively in dispensing the fluid through the dispensing orifice. In other words, the moving valve member acts directly on the fluid to improve the dispensing.
To achieve this object, the present invention provides a dispenser whose outlet valve comprises a valve seat and a moving valve member urged resiliently against said seat, the moving valve member forming piston means for delivering the fluid situated downstream towards the dispensing orifice. The moving valve member thus no longer merely lifts off its seat to allow the fluid past, but rather it actively delivers the fluid situated downstream from it towards the dispensing orifice. Thus, the fluid dispensed is not the fluid delivered from the pump chamber but rather the fluid situated in the valve chamber downstream from the moving valve member, which, when it moves, pushes the fluid through the dispensing orifice.
In an embodiment, the moving valve member is received in a valve chamber in which it moves with a small amount of clearance. Preferably, the valve chamber defines a cylindrical inside wall and the moving valve member comprises a cylindrical disk of diameter slightly smaller than the diameter of the chamber so that the peripheral edge of the disk moves with a very small mount of clearance relative to the cylindrical wall.
In another embodiment, the valve chamber defines a cylindrical inside wall provided with ribs and the moving valve member comprises a cylindrical disk having a peripheral edge in sliding contact with the ribs. The ribs define passageways between them through which the fluid can flow to go around the disk. However, as in the preceding embodiment in which the disk has a very small amount of clearance between itself and the wall of the chamber, very large head loss is generated at the periphery of the disk so that the fluid delivered from the chamber tends to displace the disk rather than flowing around it through the small amount of clearance or through the passageways defined by the ribs. The fluid delivered from the pump chamber does not pass directly to the other side of the moving valve member because of the passageway of small cross-section that it encounters at the edges of the moving valve member. Thus, the fluid comes to push the moving valve member which, itself, pushes the fluid towards the dispensing orifice. Therefore, the disk is moved very rapidly in response to the arrival of fluid under pressure, since only a very small amount of fluid can escape around the disk. There is thus no or very little damping effect in the displacement of the disk due to the fluid leaking around the disk. In this way, the disk, and more generally the moving valve member perform a hydraulic piston function by delivering the fluid situated downstream to the immediate vicinity of the dispenser. This applies although the disk is not in leaktight contact in the chamber.
In another embodiment, the moving valve member is in leaktight sliding contact in the chamber except at grooves enabling the fluid to pass towards the dispensing orifice when the mobile valve member is at the end of its stroke going away from its seat. Advantageously, the moving valve member is in sliding contact in a sleeve situated in the chamber. In which case, the sleeve defines the grooves. The moving valve member is in leaktight sliding contact with the wall of the sleeve or of the valve chamber over most of its stroke. At the end of its stroke, one or more grooves make it possible for the fluid delivered from the pump chamber to pass to the other side of the moving valve member. In which case, the disk performs a genuine piston function until it reaches the grooves. Therebeyond, the fluid that has pushed the disk can escape into the valve chamber around the disk through the grooves.
Advantageously, the dispenser device further comprises fast rate actuating means suitable for causing the volume of the pump chamber to vary rapidly and repetitively so as to generate, at the dispensing orifice, a substantially continuous jet of fluid. The use of an outlet valve as defined above in combination with fast rate actuating means is very advantageous since each time the pump chamber is actuated, the actuating takes the form of a sudden pulse which causes the moving member to react very rapidly. In addition, these sudden pulses generated by the fast rate actuating means minimize the quantity of fluid that flows around the moving valve member. It is only once the pulse has died down that the moving valve member returns to its leaktight position on its seat, thereby causing the fluid initially situated immediately behind it to pass around it to a point downstream from it, i.e. between itself and the dispensing orifice.
According to another characteristic of the invention, the pump chamber includes a wall in the form of a deformable flexible membrane on which the actuating means act.
According to another characteristic, the pump chamber, the inlet valve, the outlet valve, and the dispensing orifice are part of a first subassembly provided with fixing means for fixing to a receptacle. In addition, the actuating means are part of a second subassembly mounted removably on the first subassembly. Advantageously, the dispensing orifice is fixed relative to a reservoir on which the pump is mounted. In another embodiment, the first subassembly comprises a body and a piece connected to said body to form said pump chamber together, the piece forming the membrane. Preferably, said piece receives the outlet valve and the dispensing orifice.
By using a deformable flexible membrane instead of a sliding piston, the friction forces at the pump chamber are totally eliminated. The force necessary to deform the membrane can be set at a very low level by acting, for example, on the thickness of the membrane. The easier the membrane is to deform, the less the actuating means need to be powerful. It is thus possible to implement a dispensing device that has a very small volume. A principle of the present invention is to minimize or even eliminate the friction forces at the pump.
It should be noted that, unlike in the abovementioned prior art dispenser devices, the dispensing orifice is fixed relative to a reservoir on which the pump is mounted. It is thus possible to obtain a continuous and properly localized jet of fluid.
The invention is described more fully below with reference to the accompanying drawings which give an embodiment of the present invention by way of non-limiting example.